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Continuum model for plastic-brittle behaviour of rock and concrete
126A
discussed a~d applied to rock-like materials. In particular, elastic-brittle and plasticbrittle idealizations are considered with the fracturing affecting elastic amd plastic strains respectively. The elastic-brittle model incorporates the plasticity-llke co~ept of varying fracture surface. Also the idea of a limit (failure) locus is introduced as the stresspath dependent condition.
796011 DETERMINATION OF FORE STRUCTURE PARAM~.A'~S USING CAPII/~Y PRESSURE M E A S U ~ S , IN PAR" TICULAR BY THE C E ~ I F U G I N G PROCESS AS COMPARED WITH THE MERCURY INJECTION METHOD (IN GERMAN) Pohl, A Neue Bergbautech, vS, N4, April 1978, P2012O8 The centrifuging method is particularly suitable for rocks of low porosity and permeability.
796o;.2 PR~TMINARY
"f96oz6
STUDY OF THE REPRODUCIBILITY OF JOINT M E A S U ~ S IN ROCK West~ G • Translx~ ami Road Research Lab supplementary relx~rt 488, 1979, 16P
An investigation has been made into the reproduclbility of measurement of Joint frequency and orientation in the Lower Chalk, aml to compare measurement of Joint frequency made from stereo-photogral~hS with measurement made on site. It was foumd that measurement of Joint spacing was a subjective matter I the Jolnt distribution diagrams being different for different observers. However, measurements from stereol~O~al~hS showed no more variation than site measurements. It was found that both the dip a ~ e amd dip direction could be determined to within 6 degrees for well-defined Joints.
Contains an analysis of the unbalanced, sy~mmtric loading of a plane i~fiuite elastic wedge with a symmetric crack at the emd. Exact expressions for the stress intensity factors as fumctions of the wedge amgle and the force direction are derived. Relates to the s y ~ i c splitting of plane rectangular slabs of brittie materials, such as rock or concrete, by a wedging tool in the laboratory.
796oz7
The finite el-me~t method is applied to simulate the progressive failure of rock which is heterogeneous amd consists of various minerals a ~ / o r pores. At each step of loading with umiform displacement of the upper end of the rock model, the stresses of each element are compared with its stremgth, and the elasticity matrices of fractured elements are changed to those of the fractured state. The total load of the rock model is calculated to givm the complete loaddisplace~nent diagram in umiaxial compression.
Fracture processes 796013 THREE-DIMENSIONAL CRACK ANALYSIS Weaver ~ J Int J Solids Struct, VI3, ~ , 1977, P321-330
7~o~
Strength characteristics 796oz8
796015 CONTINUUM MODEL FOR P L A S T I C - B R I ~ BEHAVIOUR OF ROCK AND CONCRE~ Dragon, AS Mroz, Z In% J Engng Sci, VI7, N2, 1979, P121-137 Deals with a continuum model for tlme-dependent behaviour of progressively fracturing solids. The rate theory with fracture parameter is
SHEAR STRENGTH BEHAVIOUR OF SATURATED CLAYS AND THE ROLE OF THE ~ T Y V E STRESS C O N C E ~ Srid_haran, A; Venkatappa Rao, G Geotechmlque, V29, N2, June 1979, P177-193 This paper discusses the mechanisms controlling the shear atremgth behavlour of saturated kaolinite and montmorillonite clays from a detailed experimental programme based on certain theoretical considerations. In the light of the modified effective stress concept an attempt has been mad~ to explain the behaviour of the clays. Eight organle fluids of different dielectric properties, air and water have been used as pore media to vary the inter-particle forces in the conventional box shear apparatus. The influence of failure void ratio is discussed in detail.
SEPARATION BUB~Lm AT THE TIP OF A SHEAR CRACK UNDER NORMAL PRESSURE Janach, W Int J Fract, Vlk, N6, Dec 1978, R325-R327 Discusses the formation of a separation bubble in a shear crack located along an interface between two materials with different elastic constants. Reports briefly on the results of a finite element calculation of an edge crack at an interface representative of a grain boundary in a rock.
COMPUTER MODELLING OF ROCK FRACTURE IN UNIAXIAL COMPRESSION (IN JAPANESE ) Nishimatsu, Y; Okubo, S J Fac Em~mg Uuiv Tokyo, Ser A, NI6, 1978, P54-
55
Avail: TRRL, Old Wokimgham Rd, Crowthorne, Berks, UK
A method is presented for the stress a ~ s i s of plane cracks of am~ shape in a stressed three-dlm~msionsl linear elastic space. The approach utilizes a system of integral equations which is defined over the crack area only. When these equations are solved for the u r ~ n dislocations, all other quantities related to the crack and the space can then be found. The text contains sections concerning equation system d~ivation, numerical procedures, stress intensity factors, rectangular cracks, and earthquake control. Auth.
SYMMETRIC CRACKING OF A WEDGE BY CONCENTRATED LOADS 0uchterlo~, F Int J E~gng Sci, VlS, N2, 1977, Pi09-i16
7~6o~9
RAILROAD BALLAo~ SIZING AND GRADING. TECHNICAL NOTE Raymond, G P; DiyalJee, V A J Geotech Engng Div ASCE, V105, NGTS, May 1979, P676-681 Reports lab tests of plastic strain and strer%~ah of ballast in relation to ballast top size and grading.
discussed a~d applied to rock-like materials. In particular, elastic-brittle and plasticbrittle idealizations are considered with the fracturing affecting elastic amd plastic strains respectively. The elastic-brittle model incorporates the plasticity-llke co~ept of varying fracture surface. Also the idea of a limit (failure) locus is introduced as the stresspath dependent condition.
796011 DETERMINATION OF FORE STRUCTURE PARAM~.A'~S USING CAPII/~Y PRESSURE M E A S U ~ S , IN PAR" TICULAR BY THE C E ~ I F U G I N G PROCESS AS COMPARED WITH THE MERCURY INJECTION METHOD (IN GERMAN) Pohl, A Neue Bergbautech, vS, N4, April 1978, P2012O8 The centrifuging method is particularly suitable for rocks of low porosity and permeability.
796o;.2 PR~TMINARY
"f96oz6
STUDY OF THE REPRODUCIBILITY OF JOINT M E A S U ~ S IN ROCK West~ G • Translx~ ami Road Research Lab supplementary relx~rt 488, 1979, 16P
An investigation has been made into the reproduclbility of measurement of Joint frequency and orientation in the Lower Chalk, aml to compare measurement of Joint frequency made from stereo-photogral~hS with measurement made on site. It was foumd that measurement of Joint spacing was a subjective matter I the Jolnt distribution diagrams being different for different observers. However, measurements from stereol~O~al~hS showed no more variation than site measurements. It was found that both the dip a ~ e amd dip direction could be determined to within 6 degrees for well-defined Joints.
Contains an analysis of the unbalanced, sy~mmtric loading of a plane i~fiuite elastic wedge with a symmetric crack at the emd. Exact expressions for the stress intensity factors as fumctions of the wedge amgle and the force direction are derived. Relates to the s y ~ i c splitting of plane rectangular slabs of brittie materials, such as rock or concrete, by a wedging tool in the laboratory.
796oz7
The finite el-me~t method is applied to simulate the progressive failure of rock which is heterogeneous amd consists of various minerals a ~ / o r pores. At each step of loading with umiform displacement of the upper end of the rock model, the stresses of each element are compared with its stremgth, and the elasticity matrices of fractured elements are changed to those of the fractured state. The total load of the rock model is calculated to givm the complete loaddisplace~nent diagram in umiaxial compression.
Fracture processes 796013 THREE-DIMENSIONAL CRACK ANALYSIS Weaver ~ J Int J Solids Struct, VI3, ~ , 1977, P321-330
7~o~
Strength characteristics 796oz8
796015 CONTINUUM MODEL FOR P L A S T I C - B R I ~ BEHAVIOUR OF ROCK AND CONCRE~ Dragon, AS Mroz, Z In% J Engng Sci, VI7, N2, 1979, P121-137 Deals with a continuum model for tlme-dependent behaviour of progressively fracturing solids. The rate theory with fracture parameter is
SHEAR STRENGTH BEHAVIOUR OF SATURATED CLAYS AND THE ROLE OF THE ~ T Y V E STRESS C O N C E ~ Srid_haran, A; Venkatappa Rao, G Geotechmlque, V29, N2, June 1979, P177-193 This paper discusses the mechanisms controlling the shear atremgth behavlour of saturated kaolinite and montmorillonite clays from a detailed experimental programme based on certain theoretical considerations. In the light of the modified effective stress concept an attempt has been mad~ to explain the behaviour of the clays. Eight organle fluids of different dielectric properties, air and water have been used as pore media to vary the inter-particle forces in the conventional box shear apparatus. The influence of failure void ratio is discussed in detail.
SEPARATION BUB~Lm AT THE TIP OF A SHEAR CRACK UNDER NORMAL PRESSURE Janach, W Int J Fract, Vlk, N6, Dec 1978, R325-R327 Discusses the formation of a separation bubble in a shear crack located along an interface between two materials with different elastic constants. Reports briefly on the results of a finite element calculation of an edge crack at an interface representative of a grain boundary in a rock.
COMPUTER MODELLING OF ROCK FRACTURE IN UNIAXIAL COMPRESSION (IN JAPANESE ) Nishimatsu, Y; Okubo, S J Fac Em~mg Uuiv Tokyo, Ser A, NI6, 1978, P54-
55
Avail: TRRL, Old Wokimgham Rd, Crowthorne, Berks, UK
A method is presented for the stress a ~ s i s of plane cracks of am~ shape in a stressed three-dlm~msionsl linear elastic space. The approach utilizes a system of integral equations which is defined over the crack area only. When these equations are solved for the u r ~ n dislocations, all other quantities related to the crack and the space can then be found. The text contains sections concerning equation system d~ivation, numerical procedures, stress intensity factors, rectangular cracks, and earthquake control. Auth.
SYMMETRIC CRACKING OF A WEDGE BY CONCENTRATED LOADS 0uchterlo~, F Int J E~gng Sci, VlS, N2, 1977, Pi09-i16
7~6o~9
RAILROAD BALLAo~ SIZING AND GRADING. TECHNICAL NOTE Raymond, G P; DiyalJee, V A J Geotech Engng Div ASCE, V105, NGTS, May 1979, P676-681 Reports lab tests of plastic strain and strer%~ah of ballast in relation to ballast top size and grading.